Impossible to compare the 2 softwares ; it isn't the same use at all (that's why Adobe makes the two!)
- Lightroom is the perfect tool for photographers, comparing to the good old library + light box + labo when we were using films : you can archive, store, find your pictures (database functionalities), you can inspect, rate, select them (edit and catalogue capabilities), process, modify and prepare your Raw files (darkroom equivalent), export, print, or prepare for numeric use your pictures (end of the process).
Actually, a powerfull and intuitive "all in one", for 100% of your (strictly) photographic process.
- Photoshop is the absolute image creator sofware in the market; used by photographers indeed, but mostly by graphists, designers, artists, painters etc., you can find in it all the functions to create and modify any sort of picture.
As photographer you will use it ponctually, for post-processing, manipulations, artwork and graphical options.
Now, my opinion/my use : you need these two softwares!